1. Field
One or more embodiments of the inventive concept relate to a sealing apparatus, a substrate-sealing apparatus, and a substrate-sealing method used by the sealing apparatus.
2. Description of the Related Art
Recently, display devices have been replaced with thin flat panel display devices. Among the flat panel display devices, an electroluminescent display device is a self-light-emitting display device which has wide viewing angles, excellent contrast, and fast response time. Therefore, the electroluminescent display is receiving attention as a next-generation display device. An organic light-emitting display device, in which a light-emitting layer is formed of an organic material, has excellent luminance, low driving voltage, and fast response time in comparison with an inorganic light-emitting display device, and enables multi-colorization.
Typical organic light-emitting display devices have a structure in which at least one organic layer, including an emission layer, is interposed between two electrodes.
When moisture or oxygen is introduced into a typical organic light-emitting display device from the atmosphere, an electrode material may be oxidized or exfoliated to reduce the life span and the light-emitting efficiency of the typical organic light-emitting device and to deteriorate light-emitting colors.
Accordingly, when an organic light-emitting display device is manufactured, an organic light-emitting device (OLED) is usually isolated from the atmosphere and sealed to prevent moisture and oxygen from being introduced. Examples of the sealing methods include a method in which an inorganic thin film and an organic polymer such as polyester (PET) are laminated on a second electrode of the organic light-emitting display device and a method in which an absorbent is formed in an encapsulation substrate. Nitrogen gas is filled in the encapsulation substrate and a boundary of the encapsulation substrate is sealed using a sealant such as epoxy.
However, it is impossible for these methods to completely block factors such as moisture or oxygen introduced from the outside, which destroys the organic OLED. Thus, these methods may be inappropriate for the organic light-emitting display devices that are particularly vulnerable to moisture. Moreover, a process for realizing the methods is also complicated. In order to solve these problems, a method in which a frit is used as a sealant to improve adhesion between an OLED substrate and the encapsulation substrate has been designed.
Because the frit is applied on a glass substrate to seal the organic light-emitting display device, the OLED substrate and the encapsulation substrate may be completely sealed to more effectively protect the organic light-emitting display device.
According to the method in which the substrate is sealed by using the frit, the frit is applied to each of sealing units of the organic light-emitting display device, Laser beams are irradiated onto the sealing units of the organic light-emitting display device while moving a laser beam irradiation device. The frit is cured, thereby sealing the substrate by using the laser beam irradiation device.